diff --git a/CHANGELOG.md b/CHANGELOG.md
index 49a3affef..cbd749a9e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,17 +1,17 @@
-## v2.0.0-beta.4 / 2017-09-14
+## v2.0.0-beta.5 / 2017-09-21
 
 This release includes numerous changes to the new storage layer. The main changes are:
 
-* [CHANGES] Single, compacted write ahead log
-* [CHANGES] Single in-memory block with garbage collection
-* [ENHANCEMENTS] Cache series dropped via `metric_relabel_configs`
-* [ENHANCEMENTS] Pool byte buffers for scraping
+* [BUGFIX] Remove deadlock on startup when restoring WAL
+* [BUGFIX] Fix semantical races resulting in invalid persisted files
+* [BUGFIX] Correctly read back WAL in certain edge cases
+* [BUGFIX] Prevent crashes caused by changing metric representations in target's /metrics
+* [ENHANCEMENT] Overall memory usage reduction
+* [ENHANCEMENT] Serve debugging endpoints while TSDB is loading
+* [ENHANCEMENT] Healthy endpoint correctly reflects liveness during startup
+* [ENHANCEMENT] Switch to consistent usage of go-kit/log
 
-Overall the changes achieve a baseline reduction in memory consumption and reduce
-peak memory usage by 30-40% compared to the 2.0.0-beta.2 release.
-
-This release requires a clean storage directory and is not compatible with files
-created by previous beta releases.
+This release may have issues with files written by previous beta releases.
 
 ## 1.7.1 / 2017-06-12
 
diff --git a/VERSION b/VERSION
index 20c4e2607..ec7f186d3 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2.0.0-beta.4
+2.0.0-beta.5
diff --git a/vendor/github.com/prometheus/tsdb/compact.go b/vendor/github.com/prometheus/tsdb/compact.go
index a3bc7d17a..17a4da041 100644
--- a/vendor/github.com/prometheus/tsdb/compact.go
+++ b/vendor/github.com/prometheus/tsdb/compact.go
@@ -457,7 +457,7 @@ func (c *LeveledCompactor) populateBlock(blocks []BlockReader, meta *BlockMeta,
 
 		indexr := b.Index()
 
-		all, err := indexr.Postings("", "")
+		all, err := indexr.Postings(allPostingsKey.Name, allPostingsKey.Value)
 		if err != nil {
 			return err
 		}
diff --git a/vendor/github.com/prometheus/tsdb/head.go b/vendor/github.com/prometheus/tsdb/head.go
index a5ce94e45..72973c46c 100644
--- a/vendor/github.com/prometheus/tsdb/head.go
+++ b/vendor/github.com/prometheus/tsdb/head.go
@@ -190,6 +190,10 @@ func (h *Head) ReadWAL() error {
 	r := h.wal.Reader()
 	mint := h.MinTime()
 
+	// Track number of samples that referenced a series we don't know about
+	// for error reporting.
+	var unknownRefs int
+
 	seriesFunc := func(series []RefSeries) error {
 		for _, s := range series {
 			h.getOrCreateWithID(s.Ref, s.Labels.Hash(), s.Labels)
@@ -207,7 +211,7 @@ func (h *Head) ReadWAL() error {
 			}
 			ms := h.series.getByID(s.Ref)
 			if ms == nil {
-				h.logger.Log("msg", "unknown series reference in WAL", "ref", s.Ref)
+				unknownRefs++
 				continue
 			}
 			_, chunkCreated := ms.append(s.T, s.V)
@@ -230,6 +234,10 @@ func (h *Head) ReadWAL() error {
 		return nil
 	}
 
+	if unknownRefs > 0 {
+		h.logger.Log("msg", "unknown series references in WAL samples", "count", unknownRefs)
+	}
+
 	if err := r.Read(seriesFunc, samplesFunc, deletesFunc); err != nil {
 		return errors.Wrap(err, "consume WAL")
 	}
@@ -267,12 +275,10 @@ func (h *Head) Truncate(mint int64) error {
 
 	start = time.Now()
 
-	p, err := h.indexRange(mint, math.MaxInt64).Postings("", "")
-	if err != nil {
-		return err
+	keep := func(id uint64) bool {
+		return h.series.getByID(id) != nil
 	}
-
-	if err := h.wal.Truncate(mint, p); err == nil {
+	if err := h.wal.Truncate(mint, keep); err == nil {
 		h.logger.Log("msg", "WAL truncation completed", "duration", time.Since(start))
 	} else {
 		h.logger.Log("msg", "WAL truncation failed", "err", err, "duration", time.Since(start))
@@ -1038,8 +1044,6 @@ func (s *stripeSeries) getOrSet(hash uint64, series *memSeries) (*memSeries, boo
 		return prev, false
 	}
 	s.hashes[i].set(hash, series)
-
-	s.hashes[i][hash] = append(s.hashes[i][hash], series)
 	s.locks[i].Unlock()
 
 	i = series.ref & stripeMask
diff --git a/vendor/github.com/prometheus/tsdb/postings.go b/vendor/github.com/prometheus/tsdb/postings.go
index 97a29ab19..0e51b221b 100644
--- a/vendor/github.com/prometheus/tsdb/postings.go
+++ b/vendor/github.com/prometheus/tsdb/postings.go
@@ -45,7 +45,7 @@ func (p *memPostings) get(name, value string) Postings {
 	return newListPostings(l)
 }
 
-var allLabel = labels.Label{}
+var allPostingsKey = labels.Label{}
 
 // add adds a document to the index. The caller has to ensure that no
 // term argument appears twice.
@@ -53,13 +53,36 @@ func (p *memPostings) add(id uint64, lset labels.Labels) {
 	p.mtx.Lock()
 
 	for _, l := range lset {
-		p.m[l] = append(p.m[l], id)
+		p.addFor(id, l)
 	}
-	p.m[allLabel] = append(p.m[allLabel], id)
+	p.addFor(id, allPostingsKey)
 
 	p.mtx.Unlock()
 }
 
+func (p *memPostings) addFor(id uint64, l labels.Label) {
+	list := append(p.m[l], id)
+	p.m[l] = list
+
+	// There is no guarantee that no higher ID was inserted before as they may
+	// be generated independently before adding them to postings.
+	// We repair order violations on insert. The invariant is that the first n-1
+	// items in the list are already sorted.
+	for i := len(list) - 1; i >= 1; i-- {
+		if list[i] >= list[i-1] {
+			break
+		}
+		list[i], list[i-1] = list[i-1], list[i]
+	}
+}
+
+func expandPostings(p Postings) (res []uint64, err error) {
+	for p.Next() {
+		res = append(res, p.At())
+	}
+	return res, p.Err()
+}
+
 // Postings provides iterative access over a postings list.
 type Postings interface {
 	// Next advances the iterator and returns true if another value was found.
diff --git a/vendor/github.com/prometheus/tsdb/wal.go b/vendor/github.com/prometheus/tsdb/wal.go
index 27984ea0c..c52bca86d 100644
--- a/vendor/github.com/prometheus/tsdb/wal.go
+++ b/vendor/github.com/prometheus/tsdb/wal.go
@@ -71,7 +71,7 @@ type WAL interface {
 	LogSeries([]RefSeries) error
 	LogSamples([]RefSample) error
 	LogDeletes([]Stone) error
-	Truncate(int64, Postings) error
+	Truncate(mint int64, keep func(uint64) bool) error
 	Close() error
 }
 
@@ -87,7 +87,7 @@ func (w nopWAL) Reader() WALReader                       { return w }
 func (nopWAL) LogSeries([]RefSeries) error               { return nil }
 func (nopWAL) LogSamples([]RefSample) error              { return nil }
 func (nopWAL) LogDeletes([]Stone) error                  { return nil }
-func (nopWAL) Truncate(int64, Postings) error            { return nil }
+func (nopWAL) Truncate(int64, func(uint64) bool) error   { return nil }
 func (nopWAL) Close() error                              { return nil }
 
 // WALReader reads entries from a WAL.
@@ -272,8 +272,9 @@ func (w *SegmentWAL) putBuffer(b *encbuf) {
 	w.buffers.Put(b)
 }
 
-// Truncate deletes the values prior to mint and the series entries not in p.
-func (w *SegmentWAL) Truncate(mint int64, p Postings) error {
+// Truncate deletes the values prior to mint and the series which the keep function
+// does not indiciate to preserve.
+func (w *SegmentWAL) Truncate(mint int64, keep func(uint64) bool) error {
 	// The last segment is always active.
 	if len(w.files) < 2 {
 		return nil
@@ -314,7 +315,6 @@ func (w *SegmentWAL) Truncate(mint int64, p Postings) error {
 		activeSeries = []RefSeries{}
 	)
 
-Loop:
 	for r.next() {
 		rt, flag, byt := r.at()
 
@@ -328,10 +328,7 @@ Loop:
 		activeSeries = activeSeries[:0]
 
 		for _, s := range series {
-			if !p.Seek(s.Ref) {
-				break Loop
-			}
-			if p.At() == s.Ref {
+			if keep(s.Ref) {
 				activeSeries = append(activeSeries, s)
 			}
 		}
diff --git a/vendor/vendor.json b/vendor/vendor.json
index 2b639724e..2ab1a537a 100644
--- a/vendor/vendor.json
+++ b/vendor/vendor.json
@@ -871,22 +871,22 @@
 			"revisionTime": "2016-04-11T19:08:41Z"
 		},
 		{
-			"checksumSHA1": "B5ndMoK8lqgFJ8xUZ/0V4zCpUw0=",
+			"checksumSHA1": "evkeOdR0mTFS7yyREas6oa1QvHY=",
 			"path": "github.com/prometheus/tsdb",
-			"revision": "162a48e4f2c6e486a0ebf61cf9cea73a8023ef0a",
-			"revisionTime": "2017-09-19T08:20:19Z"
+			"revision": "69f105f4f9478e929ef2a7d7553a7558b1de5c84",
+			"revisionTime": "2017-09-21T12:57:51Z"
 		},
 		{
 			"checksumSHA1": "Gua979gmISm4cJP/fR2hL8m5To8=",
 			"path": "github.com/prometheus/tsdb/chunks",
-			"revision": "162a48e4f2c6e486a0ebf61cf9cea73a8023ef0a",
-			"revisionTime": "2017-09-19T08:20:19Z"
+			"revision": "69f105f4f9478e929ef2a7d7553a7558b1de5c84",
+			"revisionTime": "2017-09-21T12:57:51Z"
 		},
 		{
 			"checksumSHA1": "zhmlvc322RH1L3l9DaA9d/HVVWs=",
 			"path": "github.com/prometheus/tsdb/labels",
-			"revision": "162a48e4f2c6e486a0ebf61cf9cea73a8023ef0a",
-			"revisionTime": "2017-09-19T08:20:19Z"
+			"revision": "69f105f4f9478e929ef2a7d7553a7558b1de5c84",
+			"revisionTime": "2017-09-21T12:57:51Z"
 		},
 		{
 			"checksumSHA1": "5SYLEhADhdBVZAGPVHWggQl7H8k=",